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Have those who propose a pathogenic origin of human homosexuality ever asked why a Gay Germ should leave homosexual men so curiously undamaged overall, apart from the one effect of being gay?

We first stop to note a distinction between two kinds of hypothetical Gay Germ.

To the first kind of Gay Germ, damage it does to other organisms in the process of propagating itself is merely accidental. Experience tells us that accidents tend to be messy. So why does this “accident” cause damage that looks like it was inflicted with surgical precision?

Since results that look like precision brain surgery are unlikely to happen by mere accident, let’s turn to the second kind of Gay Germ. To this one, the damage it does is strategic. The effect it has on the host is part of its life cycle.

In the ensuing evolutionary arms race, the host strives to avoid any and all damage, while the pathogen must “insist” on inflicting the kind of damage it requires for propagation. This could conceivably result in the damage to become very localized. The host manages to eliminate all damage except for that which is essential to the pathogen.

Thus, between the two kinds of hypothetical Gay Germs, evidence of “surgical” damage not only favors the strategist, it also predicts that being gay would be essential to the spread of Gay Germ.

But isn’t that strange? Have you ever heard of rabid dogs that only want to bite other rabid dogs? A vampire’s unquenchable thirst for vampire blood?

A recent article in Nature talks about naked mole rat poo. This post is not about poo, naked mole rat’s or otherwise. Here is the sentence that triggered this post:

The rest of the [naked mole rat] colony consists of dozens of infertile subordinates that help with tasks such as foraging and defending the nest.

So let’s get to what this post is about: Various “gay gene” theories of (human male) homosexuality and the usual reason advanced against them, which is that the negative fitness impact on its carrier is simply too large for the respective gay gene to spread.

I used to agree with this reasoning for a long time, but it could rest on a crucial mistake. Consider the naked mole rat’s infertile subordinates. How do they pass their “infertility gene” to the next generation? Good question, because being infertile, they clearly don’t.

A solution to this subordinate naked mole rat infertility impossibility problem is to make this an instance of Dawkins’ extended phenotype concept and assume their infertility to be a property of their mother’s genome. Quoting Dawkins (via Wikipedia):

An animal’s behaviour tends to maximize the survival of the genes “for” that behaviour, whether or not those genes happen to be in the body of the particular animal performing it.

By analogy, then, the crucial mistake contained within the usual “inclusive fitness” refutation of gay gene theories is to assume that a homosexual man himself must be the carrier of a gay gene.

Instead, let’s consider that his homosexuality is part of his mother’s genome. Could such a gay gene spread? The naked mole rat seems to provide an existence proof that a mammalian mother can indeed benefit from sterilized offspring.

Looking over Wikipedia’s article on Biology and Sexual Orientation, not only do I not find anything inconsistent with a maternal “gay son gene”, but in fact some of the evidence (such as X chromosome linkage, birth order effects) seems quite suggestive of maternal involvement

I don’t think the idea of a gay son gene (incipient human eusociality?) can be new, but I haven’t seen it spelled out explicitly. If a reader has pointers, please comment.

Alan Bittles, in his summary of consanguinity research, notes that consanguinity prevalence is currently rising:

…as greater numbers of children survive to marriageable age, the traditional social preference for consanguineous unions can be more readily accommodated.

Looking into the future, he predicts a reversal (my boldface):

Irrespective of prevailing legislation, a future decline in the prevalence of consanguineous unions can be predicted, accompanying the expected reduction in family sizes. It seems probable that this decline will not be uniform in effect across populations but will be mainly observed in urbanized populations and among couples who share higher educational standards and later ages at marriage. The specific type of consanguineous union contracted may also prove to be an important determining factor.

Bittles also notes that consanguineous unions tend to increased fertility:

A partial explanation for these findings is the generally lower parental age at marriage and the age at the first birth of couples who are close relatives (Bittleset al. 1991, 1993).

When taken together, these effects would constitute a positive feedback loop that could push populations into a spiral of mutually reinforcing decreasing levels of consanguinity and fertility once critical thresholds are crossed.

The thought that such an outbreeding ratchet could actually be the hidden cause behind low western/urban fertility levels does not inspire confidence in the reversibility of fertility trends and future viability of these societies.

HT Steve Sailer for linking to Alan Bittles and Michael Black’s consang.net The site offers maps and tables of consanguinity/endogamy data from around the globe as well as a research summary by Alan Bittles from which the following quotes are excerpted.

Sociodemographic aspects of consanguinity

The reasons most commonly given for the popularity of consanguineous marriage can be summarized as: a strong family tradition of consanguineous unions; the maintenance of family structure and property, and the strengthening of family ties; financial advantages relating to dowry or bridewealth payments; the ease of marital arrangements and a closer relationship between the wife and her in-laws; and greater marriage stability and durability (Bittles 1994; Hussain 1999).

Although the usual account of consanguineous marriage is broadly negative and associated with low status—so much that “inbred” is usually understood as a term of derision—Bittles also notes that:

In some populations a high prevalence of marital unions between close relatives has however been reported among land-owning families, and in traditional ruling groups and the highest socioeconomic strata (Bittles 1994, 1995a).

Consanguinity and reproductive behaviour

As we have already seen in the Iceland study the price for outbreeding/exogamy may be reduced fertility. Bittles doesn’t disagree:

In general, higher total fertility rates are reported for consanguineous marriages (Bittles 1995b).

Future prospects

Irrespective of prevailing legislation, a future decline in the prevalence of consanguineous unions can be predicted, accompanying the expected reduction in family sizes. It seems probable that this decline will not be uniform in effect across populations but will be mainly observed in urbanized populations and among couples who share higher educational standards and later ages at marriage.

What went wrong for white South Africans? Farron argues that economic self-interest of individual actors in a capitalist system always trumps collective interest.

The rest of this entry is quoted from Farron (boldface added).

[… (p. 19)]

Farmers had much more political influence than other employers. They were more numerous than other employers, and their numbers were magnified by the overrepresentation of rural districts in parliament. Moreover, most farmers were Afrikaners, while most other employers were English-speaking; and farmers benefited from romantic associations among Afrikaner nationalists. In 1910 over half of the members of parliament (MPs) of the ruling SAP were farmers; in 1948 nearly half of the MPs of the victorious National Party were farmers, as were 20% of the opposition United Party MPs. Because of their political influence, farmers were the only employers who managed to avoid any government intervention in their employment practices. Consequently, agricultural employees, even in skilled and managerial jobs, came to be nearly all black despite high Afrikaner rural unemployment

[… (p. 20)]

ISCOR’s management, like most white South Africans at the time, regarded racial discrimination as the “humanitarian” policy, but was prevented from pursuing it by economic considerations. Since economic considerations exercised such a powerful influence on a government corporation, it is no wonder that private businesses could not be forced to put morality above profits.

[… (p. 21)]

The government’s Riekert Commission (1979) estimated that most of South Africa’s clothing factories were employing illegal black workers. Businesses “even made provision in their tender prices for the payment of fines”. It reported that nearly all employers complained that bureaucratic control of the black labour supply meant that they could not hire “suitable workers…within a reasonable time”, that hiring black workers involved “cumbersome procedures linked with voluminous documentation” and that this problem was particularly acute for small businesses because they could not hire special staff to deal with labour recruitment, so it absorbed much of the time and energy of management. The Riekert Report concluded that government control of labour was an “absolutely essential social security measure; even though… the abolition of such control would lead to faster economic growth”

The situation was the same in the employment of non-manufacturing labour. For example, in 1951 blacks were legally barred from skilled construction jobs, and this bar was re-enacted in 1970. Nevertheless, the Industrial Tribunal reported in 1974 that it found “alarming malpractices” on visiting building sites, with blacks “openly engaged” in nearly all types of skilled work. Hundreds of building employers were prosecuted, but the illegal employment of blacks in skilled construction jobs kept increasing.

The government knew who its enemies were. It accused them of being “prepared to sacrifice white civilization” because of their “blind worship of die Mammon van die geldmag” (Mammon of the money power)

[… (p. 22)]

Businessmen shared the dislike and fear of most white townsmen of the problems [especially crime] associated with rapid [black] urbanization and supported some controls over entry, even while they complained about restrictions on the size of the labour pool and the mobility of their own workers. Despite this ambivalence, their pressures were consistently for the erasing of controls (Lipton 1986, p.150; her italics).

[… (p. 23)]

White individuals acting as consumers were as eager as white individuals acting as employers to violate laws that they thought desirable for social reasons. “To build a house in Johannesburg meant either waiting for months for a white, expensive, legal building gang, or finding a black gang…Most customers opted for the quicker, cheaper service” (Sowell 1970, p.30). Whites acting as individuals even thwarted the one social goal that nearly every white South African thought was crucial: maintaining residential segregation. When in 1950 the national Group Areas Act systematized the hodgepodge of local segregation laws, Prime Minister Malan called it “the kernel of apartheid” (Williams 1989, p.32). But social considerations, even when enforced by Draconian legislation, could not withstand the craving of white businesses and individuals for employees. The urban non-white population tripled between 1951 and 1980, when it was eleven times what it had been in 1911 (Lipton 1986, p.401). This caused a severe housing shortage in non-white areas and consequent willingness of non-whites to pay high prices for houses in legally white areas. By the middle 1980s about half of urban non-whites lived in legally white neighbourhoods. Most of these neighbourhoods were lower-class and lower-middle-class and most of their white inhabitants voted for right-wing political parties, but they eagerly used subterfuges to circumvent the Group Areas Act to sell their houses to non-whites who offered above-market prices (Williams 1989, pp.112-14).

[… (p. 24)]

[Under] NP rule, from 1948 until 1994, all South Africa’s heads of state, most cabinet ministers, most NP members of parliament and nearly all heads of civil service departments and government corporations were members of the Broederbond (Band of Brothers) (Giliomee 1979, pp.247-9). One of the requirements for membership in the Broederbond was, “Does he give preference to Afrikaner…persons and companies in economic, public and professional life?” (Moodie 1975, p.102)

Nevertheless, the Broederbond, (and the NP, with which it was intertwined) completely failed to accomplish the goal it set itself in the 1930s: to “mobilize the volk [(Afrikaner) people] to conquer the capitalist system and to transform it so that it fits our ethnic nature”. This Volkskapitalisme would subordinate economic considerations to the aim of Afrikaners investing in and buying from Afrikaner-owned businesses (Moodie 1975, pp.203-6). Before the NP attained power, Afrikaner nationalists tried to implement this goal with boycotts of Jewish and Indian retailers, especially in small towns. However, as always, “while patriotic Afrikaners made some effort to ‘buy Afrikaans’, the rank and file have been more interested in prices, quality, design…credit terms and the location of the business” (Giliomee 1979, pp.156, 167). So, “despite all the demagoguery, the Afrikaner masses traded with Indians rather than with the less competitive Afrikaner businesses” (Williams 1989, p.107).

Coloured (mixed-race) retailers also constantly complained of “unfair” Indian competition; and hostility was even greater among black customers, who saw Indians as “exploiters”, than among white and Coloured competitors. The only major race riot in South African history was a black anti-Indian riot in Durban in 1949, in which 142 people were killed. However, as always, when non-Indians made economic decisions they chose self-interest over morality, patriotism and indignation at perceived exploitation. Consequently, competitors had to resort to government legislation. In 1950, over half a century of laws designed to curb Indian business success culminated in the provisions of the Group Areas Act that restricted Indian businesses mostly to Indian areas. But Indian businesses continued to prosper, obviously because whites, Coloureds and blacks, who collectively composed 97% of South Africa’s population, bought from them. Between 1950 and 1976 the number of moderate-sized Indian businesses in Natal, where most South African Indians live, rose from 120 to 900.

[… (p. 27)]

At the beginning of this section I quoted Nelson Mandela’s statement that an “important element of our policy…is [that] in its ownership and management, this economy increasingly reflects the racial composition of our society”. But the post-1994 black South African government has been no more successful than the Afrikaner-nationalist government that preceded it. The front-page headline of the Johannesburg Star of November 7, 1997 was “Affirmative Action Scams Exposed”. It reported that it is “commonplace” for South African “corporations [to] use black front companies and hire ‘ghost’ black directors to win contracts”. These scams have been extremely lucrative for some blacks. Between 1996 and 1999, the net income of blacks who earned over 300,000 rands a year jumped from 5 billion rands to 13.5 billion rands. But the income of middle-income blacks did not change and that of low-income blacks fell. By 1999, thanks to below-market-price sales and gifts by South African conglomerates, black-owned businesses accounted for 6% of value of shares traded on the Johannesburg Stock Exchange. That fell to 2% by February 2001; and most of that 2% was one company, Johnnic Holdings, owned by Cyril Ramaphosa, the man in charge of enforcing black economic “empowerment”.

In their reaction to the Iceland study, which showed clearly reduced fertility associated with outbreeding above about the third or fourth cousin level, many commenters seemed to prefer a default explanation of cultural causation, discounting biological cause.

[P]erhaps this dynamic is a function of the difference between genetic variance and cultural variance, and the reproductive sweep spot is the region where the former is maximized across the reproductive pair and the latter minimized. […] Gene flow across demes quickly equilibrates allele frequencies so that drift can’t fix differences. But culture may be different; whereas it is very difficult to maintain greater between group variance than within group variance with genetics for coterminous populations, it is not as difficult when it comes to culture.

Comparing with Figure 1B from the Iceland paper, this looks plausible, if only because it looks just like what any kind of additive interaction between simple inbreeding and outbreeding depression curves would look like, but still:

Yet. If cultural drift over a relatively short time in a relatively homogenous population has enough pull to cause this kind of clear reproductive disadvantage for outbreeders, can we really, as a default assumption, discount biological causation?

In the experiment equal numbers of males and females of both species were placed in containers suitable for their survival and reproduction. The progeny of each generation were examined in order to determine if there were any interspecific hybrids. These hybrids were then eliminated. An equal number of males and females of the resulting progeny were then chosen to act as progenitors of the next generation.

The fly species chosen were sufficiently interfertile to breed into almost 50% of hybrid progeny at the beginning of the experiment, but that changed very quickly:

Generation

Percentage of hybrids

1

49

2

17.6

3

3.3

Of course, the experimental condition of 100% hybrid mortality was far beyond what we’d expect from Razib’s cultural infertility effect, certainly in a place like Iceland, but then we don’t have to explain something like the near total cross-infertility of those fruit flies, either.

ABSTRACTPrevious studies have reported that related human couples tend to produce more children than unrelated couples but have been unable to determine whether this difference is biological or stems from socioeconomic variables. Our results, drawn from all known couples of the Icelandic population born between 1800 and 1965, show a significant positive association between kinship and fertility, with the greatest reproductive success observed for couples related at the level of third and fourth cousins. Owing to the relative socioeconomic homogeneity of Icelanders, and the observation of highly significant differences in the fertility of couples separated by very fine intervals of kinship, we conclude that this association is likely to have a biological basis.

I actually missed this back in 2008. It got attention from bloggers (John Hawks, Razib Khan) and the mainstream press. The Economist writes that, if outbreeding infertility is a thing, we should conclude that